Ducati Monster Forum

Moto Board => Tech => Topic started by: SQBT on June 29, 2012, 11:43:20 AM

Title: S2R800 does not pull on low revs
Post by: SQBT on June 29, 2012, 11:43:20 AM
Hi guys, I am looking for advise.

I have bought me a second Duc, an S2R800 (2005, with 9tkm, very good overall condition; Termignoni exhaust, otherwise stock) - additionally to an old M750 Dark (carburetor).

I figured out, that S2R does not pull on low revs as 750 does. Otherwise performance is very good, but in low tempo (<10km/h) I need to stay in 1st gear, otherwise engine dies. Even at 20 km/h it is still not smooth on 2nd.
(I am talking about properly warmed up engine, indeed.)

Is it normal for S2R800 or is there something I shall change?
Previous exhaust owner had an open air filter and - possibly, but not sure - another engine control block; I have all stock now. Could exhaust be the reason?
Would it help to switch to performance air filter?


Thanks in advance.

P.S.
I am not a mechanic, but not completely technically dumb either, can perform simple operations if well explained :)
Title: Re: S2R800 does not pull on low revs
Post by: Slide Panda on June 29, 2012, 11:52:34 AM
RPM range?

At 10km, that's a brisk walk, light jog - I'd expect to be in first. Same for 20km. On my 900 with shortened gearing (+3 in the rear) 2nd gear is really 45-50 Km switch. I can manage it below that, but the engine will lug.

If your 800 has stock gearing, you're just experiencing normality. It seems like the 750 make have had altered gearing.

Engine control block? Do you mean ECU (computer) or module like a Power commander?
Title: Re: S2R800 does not pull on low revs
Post by: SQBT on June 29, 2012, 12:48:17 PM
I will check RPMs on Sunday, I think, she does not like anything lower then 2-3t. I am most comfortable with it on 5t., then it is really dynamic and shows no problems at all.  Yes, walk speed, cornering in 30km/h zone, etc.

750 just pulls. when starting, I can simply release the clutch and it takes off.

>>Engine control block? Do you mean ECU (computer) or module like a Power commander?

The guy who sold me the bike and exhaust, showed a device in a size of a matchbox. But he had problems to reprogram immobilizer on my bike for it and left me the standard one. He told, I won't notice the difference unless racing, anyway. Also, it was programmed for an open air filter box, which I won't use on the street. So, I agreed.
As I understood, it was not an additional module, but a replacement for the standard one.
Title: Re: S2R800 does not pull on low revs
Post by: Slide Panda on June 29, 2012, 12:55:14 PM
Ah - so it's quite possible you have the Ducati Performance (DP) ECU. There wil be some stickers on it - that info will help clear things up.
If you do and are currently running the stock air box/ air filter and exhaust it's likely that the bike is running rich which can contribute to boggy running down low. But we need to confirm that ECU.

Do you know the final drive gearing your 750 had?

Can you tell us what the 800 has?

I suspect that the 800 has the stock gearing and the 750 didn't. Ducati has always geared things 'tall', and even more so as emissions restrictions have tightened. Using the taller ratios allows for a lower engine RPM at a given speen for emissions test standards - so lowered end performance was tossed on the alter of emissions mandate
Title: Re: S2R800 does not pull on low revs
Post by: SQBT on June 29, 2012, 02:22:43 PM
>>But we need to confirm that ECU.
Where do I find it?


>>Do you know the final drive gearing your 750 had?
Has.   [roll]

>>Can you tell us what the 800 has?

Both should have standard, but I did not buy them brand new. Is there any way to check it? 


>>I suspect that the 800 has the stock gearing and the 750 didn't. Ducati has always geared things 'tall', and even more so as emissions restrictions have tightened. Using the taller ratios allows for a lower engine RPM at a given speen for emissions test standards - so lowered end performance was tossed on the alter of emissions mandate

I see... This could be, of course...
Title: Re: S2R800 does not pull on low revs
Post by: Slide Panda on June 29, 2012, 02:31:42 PM
Quote from: SQBT on June 29, 2012, 02:22:43 PM
>>But we need to confirm that ECU.
Where do I find it?


>>Do you know the final drive gearing your 750 had?
Has.   [roll]

>>Can you tell us what the 800 has?

Both should have standard, but I did not buy them brand new. Is there any way to check it? 


>>I suspect that the 800 has the stock gearing and the 750 didn't. Ducati has always geared things 'tall', and even more so as emissions restrictions have tightened. Using the taller ratios allows for a lower engine RPM at a given speen for emissions test standards - so lowered end performance was tossed on the alter of emissions mandate

I see... This could be, of course...

Try the quote button :)
The ECU is under the gas tank.
Will look very similar to this
http://www.gothamcycles.com/servlet/the-4040/DUCATI-PERFORMANCE-MONSTER-620/Detail (http://www.gothamcycles.com/servlet/the-4040/DUCATI-PERFORMANCE-MONSTER-620/Detail)
The part numbers would be on it

Has... count the teeth. Sometimes the sprockets will be stamped with the number

Reference with the stock gearings
http://www.ca-cycleworks.com/shop/catalog/ducati/chain.html (http://www.ca-cycleworks.com/shop/catalog/ducati/chain.html)

Title: Re: S2R800 does not pull on low revs
Post by: SQBT on June 29, 2012, 04:04:42 PM
Quote from: Slide Panda on June 29, 2012, 02:31:42 PM
Try the quote button :)

Yeah... I knew there should be one :D  Nearly gave up on searching though :)


I will check the bikes on Sunday and post, thanks a lot for assistance Panda!

Title: Re: S2R800 does not pull on low revs
Post by: brad black on July 02, 2012, 06:10:46 AM
i would have thought a properly set up s2r800 should be nice at low rpm.  don't recall them being not so.
Title: Re: S2R800 does not pull on low revs
Post by: madalf71 on July 08, 2012, 08:15:19 AM
No issues at low rpm or road speed on my S2R800, in standard or modded form.
Title: Re: S2R800 does not pull on low revs
Post by: SQBT on July 17, 2012, 08:56:26 AM
Hi guys, sorry for delay, was on vacation in France with both S2R and M750 (my wife was driving the second bike). Before going, I have replaced the standard air filter with a K&N one, it does feel better.

Still, S2R definitely pulls less then M750 on low revs, I really have to watch it to keep 5-7000 rpm in the twisties to go smooth.
The lowest it allows is approximately 1.2 trpm, at 2trpm I can cruise, but feel a slight gap, if quickly opening the throttle.

I can not say it is a real problem, I already got used, anyway. It is just... 750 feels like a twin, s2r not. Perhaps M750 is modified. Will go count the teeth now :)
Title: Re: S2R800 does not pull on low revs
Post by: Slide Panda on July 17, 2012, 09:01:30 AM
Wait... 1200 RPMs? how the hell... that's what the idle speed at rest should be. The tech spec on my 900 (Injected) is about 1200 for idle

And yeah... if you're down at 2000 and give it the gas there will be a lag... you're way at the bottom of any reasonable range.

I've got to think that the 750 has a significantly different gearing than stock.

Title: Re: S2R800 does not pull on low revs
Post by: motoxmann on July 17, 2012, 09:27:29 AM
yeha no kidding, my m750 pulls like a raped ape, but below 3000rpm it's nearly useless for anything but cruising
Title: Re: S2R800 does not pull on low revs
Post by: SQBT on July 17, 2012, 02:42:33 PM
Back from the garage...    I am probably stupid, but I did not find the ECU :(  

But anyway, it sounds like I am worrying about nothing and it is just my old M750 that confuses me.

Quote from: Slide Panda on July 17, 2012, 09:01:30 AM
Wait... 1200 RPMs? how the hell... that's what the idle speed at rest should be. The tech spec on my 900 (Injected) is about 1200 for idle

And yeah... if you're down at 2000 and give it the gas there will be a lag... you're way at the bottom of any reasonable range.

I've got to think that the 750 has a significantly different gearing than stock.




Yes, that is what I am saying, when I roll, it dies below approx. 1200.  Almost same barrier with M750, but already from that point up it is explosive, while S2R gives a gap unless above approx. 4000 RPM.
I notice it especially when starting fast. With 750 I can just drop the clutch and open the throttle, it picks up. With S2R I need either to bring up the revs before, or release the clutch slower, otherwise it dies. Or, is there any better way to do it?

But, once again, it seems that it is just M750 that confuses me. I have actually no other bikes to compare with.
And, during the last week in France, I was keeping it at 5000-7000 and really enjoyed the dynamics.

Thanks a lot for help!